U.S. patent number 5,684,350 [Application Number 08/521,163] was granted by the patent office on 1997-11-04 for electromagnetic rotary actuator and housing for electronic devices.
This patent grant is currently assigned to Kayaba Kogyo Kabushiki Kaisha, Toukai Denshi Kogyo Kabushiki Kaisha. Invention is credited to Yasuhiko Hara, Katsuhito Miyoshi, Fumihiko Tsuji.
United States Patent |
5,684,350 |
Hara , et al. |
November 4, 1997 |
Electromagnetic rotary actuator and housing for electronic
devices
Abstract
A ring rotor wherein two magnets of different polarities are
disposed in an annular fashion, is supported free to rotate on a
base. Two stator coils fixed on the base face these magnets inside
of this rotor. Also provided are a switch fixed for selectively
energizing these coils, and a mechanism for holding the ring rotor
in a predetermined rotation position. Due to the use of magnets for
the rotor, brushes are unnecessary, and the ring rotor can be held
in a stop position by the holding mechanism. Througholes connecting
the inside of the housing and the outside of the housing base are
provided in a boss projecting from the base towards the inside of
the housing. Grooves are formed from the opening position of the
throughole in the base to the side walls of the housing. Bends are
provided in these grooves. Leads running from outside into the
housing are guided inside the housing via these grooves and
througholes. Leads are fixed by filling the grooves and througholes
with a filler. External forces acting on the leads are supported by
these bends and the fixed force of the filler, thereby preventing
loads from affecting wiring connections inside the housing.
Inventors: |
Hara; Yasuhiko (Tokyo,
JP), Tsuji; Fumihiko (Tokyo, JP), Miyoshi;
Katsuhito (Nagoya, JP) |
Assignee: |
Kayaba Kogyo Kabushiki Kaisha
(Tokyo, JP)
Toukai Denshi Kogyo Kabushiki Kaisha (Aichi,
JP)
|
Family
ID: |
26369185 |
Appl.
No.: |
08/521,163 |
Filed: |
August 30, 1995 |
Foreign Application Priority Data
|
|
|
|
|
Sep 8, 1994 [JP] |
|
|
6-214829 |
Feb 20, 1995 [JP] |
|
|
7-030771 |
|
Current U.S.
Class: |
310/89; 310/36;
310/93; 310/77 |
Current CPC
Class: |
H02K
5/225 (20130101); H02K 7/102 (20130101); H02K
26/00 (20130101); H02K 11/40 (20160101); B60K
37/06 (20130101); B60K 2370/126 (20190501); B60K
2370/158 (20190501) |
Current International
Class: |
H02K
5/22 (20060101); H02K 26/00 (20060101); H02K
7/10 (20060101); H02K 7/102 (20060101); H02K
005/00 (); H02K 033/00 (); H02K 007/10 (); H02K
049/00 () |
Field of
Search: |
;310/76,77,254,92,93,89,36 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Stephan; Steven L.
Assistant Examiner: Wallace, Jr.; Michael
Attorney, Agent or Firm: Jordan and Hamburg
Claims
The embodiments of this invention in which an exclusive property or
privilege is claimed are defined as follows:
1. An electromagnetic actuator, comprising:
a ring rotor having two magnets of different polarity disposed on
an inner circumferential surface of said ring rotor;
a base means for rotatably supporting the ring rotor;
two stator coils fixed on said base opposite said magnets on the
inner side of said ring rotor;
switching means for selectively energizing said stator coils;
means for holding said ring rotor at first and second positions
relative to said base means, said means for holding including
engagement holes defined in said ring rotor, an engagement member,
means for movably supporting said engagement member on said base
means to permit movement toward and away from said engagement holes
allowing detachable engagement of said engagement member with said
engagement holes of said ring rotor when said ring rotor is at said
first and second positions respectively, and means for biasing said
engagement member towards said ring rotor; and
stopper means for limiting rotation of said ring rotor to a range
inclusively defined by said first and second positions.
2. An electromagnetic rotary actuator as defined in claim 1,
wherein said actuator further comprises a timer interposed in
series with said switching means, and which shuts off current to
said coils at a predetermined time after energization begins.
3. An electromagnetic actuator comprising:
a ring rotor assembly;
a base means for rotatably supporting said ring rotor assembly;
said base means including a stator assembly;
torque means for producing bi-directional torque on said ring rotor
assembly relative to said stator assembly to rotate said ring rotor
assembly between first and second positions;
detent means for dententially holding said ring rotor at said first
and second positions without force from said torque means and
releasing said ring rotor in response to torque applied by said
torque means;
said detent means including engagement holes defined in said ring
rotor assembly, an engagement member, means for movably supporting
said engagement member on said base means to permit movement toward
and away from said engagement holes allowing detachable engagement
of said engagement member with first and second ones of said
engagement holes of said ring rotor assembly when said ring rotor
assembly is at said first and second positions respectively, and
means for biasing said engagement member towards said ring rotor
assembly.
4. An electromagnetic actuator comprising:
a ring rotor assembly;
a base means for rotatably supporting said ring rotor assembly;
said base means including a stator assembly;
torque means for producing bi-directional torque on said ring rotor
assembly relative to said stator assembly to rotate said ring rotor
assembly between first and second positions;
detent means for dententially holding said ring rotor at said first
and second positions without force from said torque means and
releasing said ring rotor in response to torque applied by said
torque means;
limiting means for limiting rotation of said ring rotor assembly to
between said first and second positions; said limiting means
including an arcuate groove formed in said stator assembly and a
boss formed on said ring rotor assembly engaging said arcuate
groove wherein an arc of said arcuate groove defines limits of
rotation of said ring rotor assembly.
5. An electromagnetic actuator comprising:
a ring rotor assembly having an armature with at least first and
second coils;
a base means including means for rotatably supporting said ring
rotor assembly;
said base means including a stator assembly having at least first
and second magnets disposed thereon with opposite poles facing said
ring rotor assembly;
means for selectively driving said first and second coils to
produce bi-directional torque on said ring rotor assembly relative
said stator assembly to rotate said ring rotor assembly between
first and second positions;
detent means for dententially holding said ring rotor assembly at
said first and second positions without force from said torque
means and releasing said ring rotor assembly in response to torque
applied by said torque means;
said detent means including engagement holes defined in said ring
rotor assembly, an engagement member, means for movably supporting
said engagement member on said base means to permit movement toward
and away from said engagement holes allowing detachable engagement
of said engagement member with first and second ones of said
engagement holes of said ring rotor assembly when said ring rotor
assembly is at said first and second positions respectively, and
means for biasing said engagement member towards said ring rotor
assembly; and
limiting means for limiting rotation of said ring rotor to a range
inclusively defined by said first and second positions.
Description
FIELD OF THE INVENTION
This invention relates to an electromagnetic rotary actuator that
performs a rotation when a coil is energized.
This invention also relates to the structure of a housing for
accommodating an electronic device such as an electromagnetic
actuator.
BACKGROUND OF THE INVENTION
In several electronically controlled suspension systems for
automobiles, there is provided a hydraulic damper that changes a
damping force according to an input signal. In these systems, a
plurality of orifices having different flow cross-sections are
arranged in parallel in an oil flowpath in the damper, and the
orifice used is changed over according to the rotation angle of a
control rod inserted in the damper. The control rod is connected to
a rotary type electromagnetic actuator, and it rotates between a
plurality of rotation angles according to signals output from a
controller.
An electromagnetic actuator of this type is disclosed for example
in Tokkai Hei 2-280653 published by the Japanese Patent Office in
1990. In this actuator, in contrast to the conventional structure
wherein current is supplied by brushes, a rotor comprising magnets
rotates when a fixed stator is energized by coils. The rotor
comprises four magnets arranged with alternating N and S poles, and
the stator comprises six coils arranged at equiangular intervals
surrounding the rotor.
The coils in this actuator are associated with the stator, and as
no current is supplied to rotating parts, there is no need for
brushes. This design has a desirable effect on the lifetime of the
actuator.
However, this electromagnetic actuator comprises a large number of
coils and a complex operation mechanism, so the cost of
manufacturing it is high and it Is difficult to make it
compact.
Further, as the rotor is held in a predetermined rotation position
by magnetism, the retaining force is lost when the current is
interrupted and the rotor may move by itself.
Insofar as concerns the housing used to house electrical devices in
automobiles such as electromagnetic actuators, solenoids and
sensors, cords, leads and wires are often made to project outwards
from the side or edge. This wiring may be connected to electrical
circuits in the chassis of the automobile via connectors. In the
area leading to the inside of the housing, connections are made to
circuit components of devices such as coils via terminals provided
in the housing.
However, if the wiring or housing is under a load during vehicle
assembly or repair, the load may affect terminal connections inside
the housing so as to cause a break in the wiring. Such a break may
also be caused when connections are repeatedly subjected to
vibration.
Moreover if wiring and circuit components of devices are connected
via relays such as terminals, space must be reserved for these
relays in the housing, and it is thus more difficult to make the
housing compact.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to simplify the
construction of an electromagnetic rotary actuator and its
operation mechanism.
It is a further object of this invention to make sure the rotor
stops moving after current is shut off.
It is still a further object of this invention to optimize the
layout of the wiring inside the housing of electrical devices such
as electromagnetic actuators.
It Is still a further object of this invention to make the housing
more compact.
In order to achieve the above objects, this invention provides an
electromagnetic actuator comprising a ring rotor having two magnets
of different polarity disposed on an inner circumferential surface
of the rotor, a base for supporting the ring rotor such that the
rotor is free to rotate, two stator coils fixed on the base
opposite the magnets on the inner side of the ring rotor, a
switching mechanism for selectively energizing the stator coils,
and a mechanism for holding the ring rotor in a predetermined
rotation position.
It is preferable that the holding mechanism comprises a plurality
of engaging holes formed at predetermined positions on the ring
rotor, a positioning member engaging detachably with the engaging
holes, and a member for pushing the positioning member toward the
ring rotor.
It is also preferable that the actuator further comprises a stopper
for limiting the rotation of the ring rotor beyond the
predetermined rotation position.
It is also preferable that the actuator further comprises a timer
interposed in series with the switching mechanism, and which shuts
off current to the coils at a predetermined time after energization
begins.
This invention also provides a housing for housing an electrical
device in a space defined by a base and side walls in which an
electrical lead is led to the device from outside the housing. The
housing comprises a boss projecting into the housing from the base,
a throughole passing through the boss and opening to the outside of
the housing, a groove of predetermined depth formed on the base
external surface of the housing, and extending from the opening of
the throughole in the base to one of the side walls, and a bend
provided at a predetermined position in the groove.
It is preferable that the lead is fixed on the inside of the
grooves by a filler.
It is also preferable that the lead is comprises a core covered by
a sheath, and the througholes comprise a first throughole opening
into the housing having a diameter larger than a diameter of the
core and smaller than an outer diameter of the sheath, and a second
throughole connected to the first throughole and opening outside
the housing having a diameter larger than the outer diameter of the
sheath.
It is also preferable that the housing further comprises a clamp
disposed on the side walls in the vicinity of the groove for
holding the lead.
The details as well as other features and advantages of this
invention are set forth in the remainder of the specification and
are shown in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical sectional view of an electromagnetic rotary
actuator according to this invention.
FIG. 2 is a horizontal sectional view of the electromagnetic rotary
actuator.
FIG. 3 is a set of schematic horizontal sectional views of the
electromagnetic rotary actuator showing rotation positions of a
ring rotor according to this invention.
FIG. 4 is a plan view of a retaining mechanism of the ring rotor
according to this invention.
FIG. 5 is an enlarged plan view of a part of FIG. 4.
FIG. 6 is a vertical sectional view of an oblong hole and a damper
according to this invention.
FIG. 7 is a control circuit diagram of coils according to this
invention.
FIG. 8 is similar to FIG. 7, but showing a second embodiment of
this invention.
FIG. 9 is similar to FIG. 3, but also showing the second
embodiment.
FIG. 10 is a rear view of a housing according to a third embodiment
of this invention.
FIG. 11 is a sectional view of the housing taken along a line
XI--XI in FIG. 10.
FIG. 12 is a sectional view of the housing taken along a line
XII--XII in FIG. 10.
FIG. 13 is similar to FIG. 11, but showing a wiring in place.
FIG. 14 is similar to FIG. 10, but showing the wiring in place.
FIG. 15 is a horizontal sectional view of a fixed part of a cord
according to the third embodiment.
FIG. 16 is similar to FIG. 15, but showing a possible
variation.
FIG. 17 is a vertical sectional view of a brushless motor according
to a fourth embodiment of this invention.
FIG. 18 is a schematic plan view of the brushless motor.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 of the drawings, an electromagnetic actuator is
provided with a housing 1 having a circular cross-section and a
ring rotor 4 free to rotate inside the housing 1.
As in the prior art, this electromagnetic actuator serves to rotate
a control rod in a hydraulic damper of an automobile, and forms a
part of an electronically controlled suspension system.
The ring rotor 4 has a cylindrical shape with an open end, and it
is housed in the housing 1 such that its open end faces the base of
the housing 1.
The housing 1 is enclosed by a cover 10.
A throughole 2A is formed in the center of the housing 1. A joint
60 connected to the aforesaid control rod passes through this
throughole 2A from outside the housing 1 such that the joint is
free to rotate. The tip of the joint 60 penetrates a bearing 7
pressed into the housing 1 and is joined inside the bearing 7 to a
rotor shaft 6 fixed to the center of the ring rotor 4.
The rotor shaft 6 is supported by the bearing 7 so as to permit
free rotation of the ring rotor 4 relative to the housing 1.
Two magnets 5A, 5B are fixed facing each other on the inner
circumference of the ring rotor 4 as shown in FIG. 2. The magnets
5A, 5B have an arc-shaped horizontal cross-section, the inner
circumferences of the magnets 5A and 5B being magnetized as S and N
poles respectively.
Two cores 2 are fixed on the inner side of the magnets 5A, 5B in
the housing 1. The cores 2 are pressed over the outer circumference
of the bearing 7, and are disposed symmetrically on either side of
the bearing 7. Coils 3A, 3B are wound on the core 2.
A boss 12 for guiding leads 31-33 that energize these coils project
upwards from the base of the housing. The leads 31-33 pass through
the boss 12, are led out together from the side of the housing 1 by
a harness 30, and are connected to a control circuit described
hereinafter.
The leads 31-33 supply power to the coils 3A, 3B respectively, a
lead 32 being an earth wire. The coils 3A, 3B are wound in such a
direction that the end face of the core adjacent to ring rotor 4
around which an energized coil is wound, becomes magnetized as a S
pole whichever coil is energized.
A holder 11 on the base of the housing 1 projects towards the ring
rotor 4 in such a position that it does not interfere with the
coils 3A, 3B and boss 12. The holder 11 is formed in the shape of
an open-ended cylinder, this holder 11 housing a detent ball 8 that
acts as a positioning member of the ring rotor 4 and a spring 9
that pushes this ball 8 toward the ring rotor 4 via a retainer
8A.
Engaging holes 4A, 4B that engage detachably with the ball 8, are
formed at a 60.degree. angular interval on the base of the ring
rotor 4 as shown in FIG. 4.
When the ring rotor 4 rotates, the ball 8 pushed by the spring 9
rolls over in contact with the base of the rotor, and enters an
engaging hole 4A(4B) at a predetermined rotation position. A
resistance opposing the rotation of the ring rotor 4 from this
position is then produced by the ball 8 and hole 4A(4B) according
to the elastic force of the spring 9 so as to fix the position of
the ring rotor 4 and hold it.
The engaging position of the ball 8 and hole 4A(4B) corresponds to
a preset rotation position of the control rod in the hydraulic
damper.
A stopper pin 40 projects towards the base of the ring rotor 4
outside the coil 3A of the core 2. The stopper pin 40 passes
through an arc-shaped oblong hole 41 formed in the base of the ring
rotor 4 as shown in FIGS. 4-6. The length of the hole 41
corresponds to the angular interval of the two holes 4A, 4B, rubber
dampers 42 being fitted at its two ends.
Passage of current through the coils 3A, 3B via the leads 31-33 is
controlled by a control circuit shown in FIG. 7. Current from a DC
power supply 52 is led to a switch 51 via a timer 50, and the
switch 51 supplies this current selectively to either a contact
connected to the coil 3A via the lead 31, or a contact connected to
the coil 3B via the lead 33. The current supply time is controlled
by the timer 50. The timer 50 is reset when the switch 51 is
switched over, and supply of current to the switch 51 is shut off
when a fixed time has elapsed after the switch-over.
The switch-over of the switch 51 is performed for example according
to a command from a controller in the electronically controlled
suspension system.
The contacts S and H in FIG. 7 correspond to soft and hard damping
forces. FIG. 3(a) corresponds to the state when the switch 51 is
set to S, and FIG. 3(b) corresponds to the state when the switch 51
is set to H.
When the switch 51 is set to the contact H, the coil 3B is
energized via the lead 33, and the end of the core 2 that passes
through the coil 3B is magnetized as a S pole as shown in FIG.
3(a). The inner circumference of the magnet 5A facing the end of
the core 2 is also magnetized as a S pole, hence, due to the
repulsion between these S poles and the attraction between the S
pole of the core 2 and the N pole of the inner circumference of the
magnet 5B, the ring rotor 4 rotates to the position shown in FIG.
3(b). Then, the magnet 5B of which the inner circumference is
magnetized as a N pole faces the end of the core 2 which is a S
pole and the ball 8 enters the hole 4B, so the rotation of the ring
rotor 4 stops.
Even if the ring rotor 4 would overshoot the stop position due to
inertia, the stopper pin 40 comes into contact with the damper 42
at the end of the oblong hole 41, so rotation of the rotor 4 beyond
this position is prevented. The ring rotor 4 is therefore brought
to rest accurately in the predetermined position. The control rod
joined to the rotor 4 via the joint 60 also rotates accurately to
the position wherein a hard damping force is generated.
After the ring rotor 4 has stopped rotating, when a set time has
elapsed, the timer 50 shuts off current to the switch 51, hence
there is no need for concern that the coil 3B will overheat due to
continued energization. Subsequently, the ring rotor 4 is held in
the stop position by a retaining force due to the engaging of the
ball 8 in the hole 4A and by a anti-rotating force due to the
contact of the stopper pin 40 and damper 42, until the switch 51 is
again switched over. As power is used only to operate the actuator
and not to hold it in position after operation, the actuator does
not consume much power.
When the switch 51 is switched over to the contact S, the end of
the core 2 passing through the coil 3A faces a S pole. The inner
circumference of the magnet 5A facing this S pole is magnetized as
a S pole, so due to the repulsion between these S poles and to the
attraction between the S pole of the core 2 and the N pole on the
inner circumference of the magnet 5B, the ring rotor 4 rotates from
the state of FIG. 3(b) to the state of FIG. 3(a). The stopper pin
40 then comes into contact with the damper 42 at the opposite end
of the oblong hole 41 and the ball 8 engages with the hole 4A, so
the rotation of the ring rotor 4 stops and the rotor is held in its
stop position. Due to this action, the control rod rotates to the
position where a soft damping force is generated.
Hence, the ring rotor 4 rotates between two positions determined by
the ball 8 and the engaging holes 4A, 4B according to the switching
operation of the switch 51, and the control rod is rotated
accurately between a position that sets a hard damping force and a
position that sets a soft damping force.
In this actuator, the ring rotor 4 with fixed magnets 5A, 5B
rotates, and the coils 3A, 3B that perform energization do not
rotate. There is therefore no need to provide brushes to energize
the coils, and there is no chance of faulty operation due to poor
brush contacts. Also, the construction of the actuator is simpler
insofar as there are no brushes.
As the point of action of the magnetic force rotating the ring
rotor 4 is situated close to the outer circumference of the
actuator, a sufficiently large rotation torque can be applied to
the control rod.
FIGS. 8 and 9 show a second embodiment of this invention.
In this actuator, as shown by the control circuit of FIG. 8, the
switch 51 is set to the minus side of the power supply 52 and the
energization direction of the coils 3A, 3B is set to be opposite to
that of the first embodiment.
In this case, when the switch 51 is set to the contact S, a current
flows in the coil 3A in an opposite direction to that of the first
embodiment due to leads 61, 62, and the end of the core 2 passing
through the coil 3A is magnetized as a N pole as shown in FIG.
9(a). As the inner circumference of the magnet 5A facing this N
pole is also magnetized as a N pole, there is a repulsion between
these poles and an attraction between the N pole of the end of the
core 2 and the S pole of the inner circumference of the magnet 5B.
The ring rotor 4 therefore rotates in the direction shown by the
arrow in the diagram so as to reach the position of FIG. 9(b), and
the control rod rotates to a hard damping force setting
position.
When the switch 51 is switched over from the contact H to the
contact S in the state of FIG. 9(B), current flows in the coil 3B
in an opposite direction to that of the first embodiment due to the
lead 61 and a lead 63, so the end of the core 2 passing through the
coil 3A is magnetized as a N pole. As a result, there is a
repulsion between this N pole and the N pole on the inner
circumference of the magnet 5A, and an attraction between this N
pole and the S pole of the inner circumference of the magnet 5B, so
the ring rotor 4 rotates clockwise to reach the position of FIG.
9(a). The control rod therefore rotates to a soft damping force
setting position.
The same effect is obtained according to the second embodiment as
according to the first embodiment.
Next, a third embodiment of this invention will be described with
reference to FIGS. 10-16. The housing shown in FIG. 10 is a
cylindrical member with a base that houses a stator and rotor of a
motor, not shown, and is provided with a clamp 5 that bundles leads
together on the rear surface.
The upper end of the housing 1 has an opening 1C, and this opening
1C is sealed by a cover, not shown, after the motor is installed.
An effectively circular base 1A is formed at the bottom of the
housing 1, this base 1A having an axial hole 6 to allow a motor
shaft, not shown, to pass through it.
A pair of brackets 10 project at predetermined positions on the
side walls 1B of the housing 1 as shown in FIG. 10. The brackets 10
are formed effectively in the same plane as the opening 1C, the
clamp 5 being disposed so as to subtend effectively equal angles at
these brackets 10.
A boss 9 projects upwards on the base 1A of the housing 1 as shown
in FIG. 2 in order to guide the cord 7 from the clamp 5 to the
inside of the housing 1 as shown in FIG. 13. The cord 7 comprises
an electrically conducting core covered with a non-electrically
conducting sheath.
Througholes 4 and througholes 3A-3D are formed in the boss 9 as
shown in FIG. 10. The througholes 3A, 3B and the througholes 3C, 3D
respectively form pairs, and are disposed in symmetrical positions
about a center line in the housing 1. All the througholes are
effectively parallel to the shaft axis of the axial hole. The
diameters of the througholes 3A-3D are arranged to be larger than
the diameter of a core wire 7A of the cord 7, and smaller than the
outer diameter of the sheath of the cord 7.
The througholes 4 are formed so as to be continuous with the lower
parts of the througholes 3A-3D, and open to the outside of the base
1A. The inner diameters of the througholes 4 are set to a size that
allows the cord 7 to pass through it when sheathed.
Grooves 2A-2D are formed on the outer surface of the base 1A from
the openings of the througholes 4 to the clamp 5. The width and
depth of the grooves 2A-2D are set to larger values than the outer
diameter of the cord 7.
In FIG. 10, the grooves 2A and 2D that run to the clamp 5 from the
througholes 4 connected with the througholes 3A, 3D, are first
effectively parallel, and after bends 21 that curve towards each
other and bends 22 where they are again parallel, they reach the
boundary with the side wall 1B of the housing 1.
The grooves 2B and 2C that run to the clamp 5 from the througholes
4 connected with the througholes 3B, 3C, are first effectively
linear and approach each other at a predetermined angle, then they
change direction at bends 23 so that they are parallel, and reach
the boundary with the side wall 1B of the housing 1.
The grooves 2A-2D are parallel and equidistant from each other at
the boundary.
The clamp 5 comprises a roof 5A effectively parallel with the upper
edge of the housing 1 forming the opening 1C, and a stop 5B having
a notch 50, as shown in FIG. 11.
The grooves 2A-2D first bend toward the roof 5A from the boundary
of the base 1A and side wall 1B as shown in FIG. 11, then their
depth gradually decreases and finally becomes zero so that they
merge with the side wall 1B.
The cord 7 is passed respectively through the througholes 3A-3D by
inserting the core 7A, bared by peeling a predetermined amount of
sheath at the end, from the througholes 4. The tip of the core 7A
projects at a predetermined height in the housing 1, and is
connected to coils and other circuit components, not shown.
The cord 7 runs to the clamp 5 from the througholes 4 via the
grooves 2A-2D. After the cord 7 has been wired, the througholes 4
and grooves 2A-2D are filled with a filler 8 as shown in FIG. 15 so
as to fix the cord 7 in the througholes 4 and grooves 2A-2D. This
filler 8 may be a resin or an adhesive.
The cord 7 which is bent effectively at right angles from the base
1A to the side wall 1B, reaches the roof 5A, curves again and
projects beyond the stop 5B to the outside. When these cords 7 are
fitted to the clamp 5, they are led one at a time from the notch 50
to be embedded inside the stop 5B. In this way, four cords 7 fitted
to the clamp 5 are held inside the stop 5B by elasticity of the
sheath. The stop 5B is therefore previously formed with dimensions
suitable for holding the four cords 7. The four cords 7 projecting
from the clamp 5 are connected to connectors, not shown.
The cords 7 are fixed by embedding in the grooves 2A-2D and
througholes 4 by means of the filler 8. As they are led to the side
wall 1B via the bends 21-23, the tension acting on the cords 7 when
the motor is fitted as in an automobile or the like is supported at
the bends 21-23 and also supported in the fixed part by the filler
8. This makes it difficult for the cords 7 to become detached from
the base 1A under the effect of external forces, suppresses the
transmission of loads due to external forces acting on connections
with circuit components inside the housing, and prevents breaks in
connection wiring.
As the cords 7 guided from the base 1A to the side wall 1B are
first attached to the clamp 5 before continuing to the outside, the
clamp 5 has the function of protecting the cords 7 against external
forces acting on the housing 1 or cords 7. From a structural
viewpoint, therefore, the cords 7 embedded in the base 1A are not
easily affected by non-tensile forces such as forces acting to
detach the cord from the base 1A, hence it is unlikely that the
cords 7 will be damaged by external forces.
The grooves 2A-2D formed continuously from the base 1A to the side
wall 1B prevent the cords 7 from sacking out of the housing 1, and
the base 1A is effectively smooth. It is therefore easy to position
and support the housing 1 when the motor is fitted to a vehicle,
and there is greater freedom of choice in deciding an installation
position in a limited space. Also, as the cords 7 do not stick out
of the housing 1, the motor itself may be made more compact.
When the motor is assembled, and the cords 7 with cores 7A exposed
over a predetermined length at their tips are passed through the
througholes 3A-3D from the througholes 4, the cores 7A having a
fixed length project inside the housing 1 from the througholes
3A-3D. The cores 7A having a preset length therefore project inside
the housing 1, soldering of the cores 7A to circuit components,
etc. is easy, and assembly operations are rendered more efficient.
As the terminals used in the prior art are not necessary, the
number of parts can be reduced and manufacturing costs can be
lowered. As there is no need for space to house the terminals, it
will be understood that this also contributes to making the motor
compact.
Instead of having the filler 8 completely fill the grooves 2A-2D,
it may also be used to fill only the space between the vicinity of
the bases of the grooves 2A-2D and the cords 7.
FIGS. 17 and 18 show an example of applying the aforesaid housing
to a brushless motor. In this motor, a cylindrical bearing 16
projects inside the housing 1 from an axial hole 6 in the center of
the housing 1. A rotor shaft 13 of a ring rotor 12 is supported on
the inner circumferential surface of this bearing 16. The ring
rotor 12 is housed in the housing 1, and sheathed by a cover 11.
The rotor shaft 13 is joined to a load, not shown, via a joint 17
attached to the shaft 13 in the bearing 16.
The ring rotor 12 comprises four magnets 14 having an arc-shaped
cross-section fixed on the inner circumference of a cylindrical
part 12A so as to form a ring. Three core poles 15 which extend
radially at 120.degree. intervals are fixed on the inner surfaces
of these magnets 14 in the housing 1 with the bearing 16 as center,
and coils 18A-18C are wound on these poles 15.
Bosses 90, 91 project effectively parallel to the rotor shaft 13
from the base 1A into the housing 1. One end of a cord 71 for
supplying power to the coil 18A and one end of a cord 73 for
supplying power to the coil 18C, are passed through the boss 90.
One end of a cord 72 for supplying power to the coil 18B and a cord
74 for earthing the coil 18A-18C, are passed through the boss 91.
These cords 71-74 are embedded in the grooves 2A-2D and througholes
4 via the filler 8, run to the side wall 1B via the bends 21-23,
and are led to the outside via the clamp 5 as described
hereintofore.
The coils 18A-18C are connected to the cords 71-74 of which the
cores project from the bosses 90, 91.
The cords 71-74 are connected to circuit components without any
need of joint members such as terminals, so the housing 1 may be
made compact and lightweight. The cords 71-74 are supported against
axial forces at the bends 21-23, and as the cords 71-74 are fixed
by the filler 8, the connections between the cores of the cords
71-74 and the coils 18A-18C are not affected by loads. As a result,
broken wires do not easily occur in the connections.
The aforesaid embodiment was described in the case of a motor,
however it is not limited to motors and may also be applied to
electromagnetic actuators or other electrical devices in
general.
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